Resolution of Respect for Paul A. Keddy 1953–2023: Ecologist, Conservationist, Naturalist

Professor Paul A. Keddy peacefully passed away at his home in Carleton Place, Ontario on December 26, 2023. He will forever be regarded for his seminal contributions to wetland ecology (Keddy 2023), ecological competition (Keddy 2001), and plant ecology (Keddy 2017). His creativity and innovation advanced our conceptual understanding of plant community assembly, and he dedicated his career to applying scientific principles to the sustainable management of natural landscapes and to the conservation of species that call these landscapes home. Norm Cyril Keddy and Dorothy Jean Keddy brought their son Paul Anthony Keddy into the world in 1953 in London, Ontario. From a very early age, Paul never hesitated to get his feet wet, whether he was conducting science fair projects on turtle conservation, observing salamanders and frogs in his beloved wetlands, or paddling down the Mississippi River on a plywood canoe. Paul's time working as a naturalist at the Algonquin Park Museum for three summers from 1971 to 1973 cemented his desire to study the natural world and to protect it (Fig. 1A). Paul studied biology (1974) at York University and obtained his Ph.D. in plant ecology (1978) from Dalhousie University under the mathematical ecologist E.C. Pielou. He served as an assistant professor at the University of Guelph (1978–1982), as an associate and full professor at the University of Ottawa (1982–1999), and as a professor and Schlieder Endowed Chair for Environmental Studies at Southeastern Louisiana University (1999–2007). Photo courtesy of Ian Keddy, Paul's son. Paul constructed one of the greatest experimental, fully replicated natural marsh facilities in the world, an ecological equivalent of the radio telescope, in coastal Louisiana (Fig. 2A). The research was groundbreaking due to its complexity and scale, and its ability to determine the relative importance of competition, herbivory, and sediment as filters in controlling the species pool of a coastal marsh (Geho et al. 2007, McFalls et al. 2010). A natural extension of Paul's foundational research on wetland plant communities was his prize-winning synthesis, Wetland Ecology: Principles and Conservation (Keddy 2023), now in its third and very recently completed edition. This book presents central and unifying themes of wetland community ecology over the global range of wetlands, highlighting general principles in the novel framework of causal factors—properties common to all wetlands, including hydrology, fertility, disturbance, competition, and herbivory; the variation in which produces the range of wetland communities and controls their diversity, zonation, and ecological services. As reviewers have said, “Paul Keddy's Wetland Ecology is quite simply one of the best books about wetlands that exists today. It should be required reading for wetland managers” (Christie 2010), and “Keddy clearly states his objectives, one of which he draws from Bernard Shaw: ‘to impress the strong, intimidate the weak, and tickle the connoisseur.’ Keddy has succeeded.” (Whigham 2002). In 2007, Paul was awarded the Merit Prize by the Society of Wetland Scientists. Photo courtesy of Ian Keddy, Paul's son. Paul viewed competition as an ecological force as fundamental to ecosystems as gravity is to Newtonian dynamics. His book Competition (Keddy 2001), now in its second edition, synthesizes the vast empirical literature on ecological competition. Instead of studying competition between pairs of species, with which the literature was replete in the 1980s, Paul took a new approach and designed experiments to study how competition changed communities of species along natural environmental gradients (Gaudet and Keddy 1988, Wilson and Keddy 1991). His work showed that plant species can be organized into competitive hierarchies; the more fertile the site, the greater the asymmetry of the competitive interaction, and the position of plants in hierarchies is relatively invariant along environmental gradients (Keddy and Shipley 1989, Keddy et al. 1994, Shipley and Keddy 1994). Paul made advances in developing the theory of centrifugal organization which suggests how competition gradients might organize plant communities (Keddy 1990, Keddy and MacLellan 1990, Wisheu and Keddy 1992). The model links high competition with low diversity. It shows that rare species are most often found in peripheral habitats, which are often most at risk, indicating that protecting peripheral habitats is critical for conserving biodiversity. It also shows that by increasing fertility and reducing natural disturbance, humans can push wetlands from species-rich peripheral habitats to densely vegetated core habitats, thereby reducing their diversity. It is a model of considerable significance for wetland management, restoration, and conservation. Over 30 years ago, Paul suggested that in order to find general predictive patterns in ecology, ecologists should examine how species pools are filtered by environmental factors through selection on functional traits (Keddy 1990, 1992a,b). He rigorously focused on deciphering the rules that drive ecological organization using both natural and experimental plant communities. Across saline coastal wetlands, Great Lakes wetlands, freshwater marshes, swamps, wet savannas, lakeshores, and riverine wetlands of central, southern and eastern North America, Paul examined the relationships between environmental factors (e.g., flooding, wave energy, fertility, water depth, ice scour, and competition) and functional traits of wetland plants (Shipley et al. 1989, Keddy et al. 1998), and drove efforts to derive general trait-based assembly rules for ecological communities (Weiher and Keddy 1995, 1999). I was fortunate to have worked closely with Paul on our book A Framework for Community Ecology: Species Pools, Filters and Traits (Keddy and Laughlin 2022), which is based on the theoretical framework that he originally outlined in his two well-known papers published in 1992 (Keddy 1992a,b). His early ideas were important catalysts that galvanized international interest in functional traits and their influence on community assembly and ecosystem functioning. I recall the day with great fondness when Paul asked me to join him on this effort. We sat on his back deck overlooking a beaver pond, called blue jays down from the trees to take peanuts set on the rail, and enjoyed a glass of his favorite New Zealand Sauvignon Blanc. Paul was not just an ecologist; he was a great conversationalist and scholarly polymath. Our ecological chats frequently digressed into philosophical questions that probed the depths of classical literature, our favorite plays, and other great works of art. All of his book covers are adorned with original artwork because, for one, they are beautiful and, two, because he thought art was important and that artists should be supported. Anyone who has read a book by Paul Keddy immediately feels refreshed. He abhorred stale prose and injected his personality into all of his books; he allowed room on the page for his words to breathe, like that of Sauvignon Blanc. Paul and his wife Cathy (who passed away in 2022) were a conservation power couple, if you will. Together, they successfully lobbied for the establishment of nationally significant nature reserves in Nova Scotia and worked tirelessly to conserve forests and wetlands around their home in Carleton Place, Ontario. The International Law Association bestowed upon Paul a National Wetlands Award for Science Research because he “repeatedly carried his work beyond the reporting of results to address conservation and management implications in wetlands and to further the theoretical understanding of how wetland plant communities function.” In 2017, he received the Lifetime Achievement Award from the Society of Wetland Scientists, and his leadership was also recognized by the Government of Canada which awarded him the Meritorious Service Medal for ecosystem conservation. And, you would never guess, but Paul accomplished all of this despite becoming chronically ill in 1990, suffering pericarditis and neurological disorders. Thankfully, he partially recovered from severe illness, but chronic fatigue syndrome plagued him for the rest of his life, rendering him unable to work more than half time and having to decline most offers for international engagements. Thus in 2007, he left the halls of academe to work as an independent scholar in his forest (longer than Thoreau but not quite as long as St. Francis), where he lived and worked for many productive years. In such a condition, most people would likely have stopped working altogether, but not Paul. He had too much to say and so he wrote until his very last days. His significant accomplishments under such adversity set an admirable example for all ecologists, for as Albert Schweitzer said, “Example is not the main thing in influencing others; it is the only thing.”

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